body {
    padding-top: 50px;
    padding-bottom: 40px;
    color: #5a5a5a;
}
/* 轮播广告 */
.carousel {
    height: 100%;
}
.carousel .item {
    height: 100%;
    background-color: #000;
}
.carousel .item img {
    height: 100%;
}
.carousel-caption {
    z-index: 10;
}
.carousel-caption p {
    margin-bottom: 20px;
    font-size: 20px;
    line-height: 1.8;
}
#xiazai{
    border: 0;
    color: #202020;
    background: #4891d1;  
    /* #62c077 */
}
#xiazai:hover{    
    color: white;
    background: #242424; 
}
/* 简介 */
.summary {
    padding-right: 15px;
    padding-left: 15px;
}
.summary .col-md-4 {
    margin-bottom: 20px;
    text-align: center;
}
/* 特性 */
.feature-divider {
    margin: 40px 0;
}
.feature {
    padding: 30px 0;
}
.feature-heading {
    font-size: 50px;
    color: #2a6496;
}
.feature-heading .text-muted {
    font-size: 28px;
}
/* 响应式布局 */
@media (max-width: 768px) {
    .summary {
        padding-right: 3px;
        padding-left: 3px;
    }
    .carousel {
        height: 200px;
        margin-bottom: 30px;
    }
    .carousel .item {
        height: 200px;
    }
    .carousel img {
        min-height: 200px;
    }
    .carousel-caption p {
        font-size: 16px;
        line-height: 1.4;
    }
    .feature-heading {
        font-size: 34px;
    }
    .feature-heading .text-muted {
        font-size: 22px;
    }
}
/* @media (min-width: 992px) {
    .feature-heading {
        margin-top: 120px;
    }
} */